CN119666770A - Gas concentration measuring device and method - Google Patents
Gas concentration measuring device and method Download PDFInfo
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- CN119666770A CN119666770A CN202311206186.1A CN202311206186A CN119666770A CN 119666770 A CN119666770 A CN 119666770A CN 202311206186 A CN202311206186 A CN 202311206186A CN 119666770 A CN119666770 A CN 119666770A
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Abstract
The invention relates to a gas concentration measuring device and method, which comprises a gas detecting cavity, a temperature sensing component, a pressure sensing component, a light source supplying device and a light sensing device, and is used for measuring the gas concentration of a gas to be measured (such as ozone). The temperature sensor and the pressure sensor respectively measure the temperature and the pressure of the gas to be measured. The light source supply device uses UV-LED as the ultraviolet light source, and provides the first detection beam and the correction beam with different ozone absorption brightness, and then uses the light splitting component to separate the first detection beam and the correction beam into the light splitting component passing through the gas to be tested and the light splitting component not passing through the gas to be tested. The light sensing device can measure the intensity of the first detection beam and the correction beam, respectively. By comparing the above light intensities, the concentration of ozone gas can be calculated by Beer-Lambert law.
Description
Technical Field
The present invention relates to a measuring device and a measuring method, and more particularly, to a measuring device and a measuring method for gas concentration.
Background
As industry evolves, a wide variety of gases are often used in a variety of industrial or living environments. For example, ozone is often used in sterilization equipment and semiconductor wafer manufacturing, but the current instruments for measuring ozone concentration have failed to meet the requirements of accurate, stable and fast feedback of ozone concentration. The existing ozone concentration measuring instrument adopts an ultraviolet light absorption brightness method, ultraviolet light is emitted by an ultraviolet light source to penetrate through ozone in a quartz glass tube, and after a light sensing signal is measured by using a light sensor, the concentration of the ozone is calculated by using the Beer-lambert law (Beer-Lambert Equation).
However, the existing ozone concentration measuring instrument mainly adopts a low-pressure mercury lamp as an ultraviolet light source, and the low-pressure mercury lamp can provide the ultraviolet light source close to an ozone absorption spectrum, but the low-pressure mercury lamp technology has the following defects that (1) long preheating time is needed, and measurement can be carried out only at intervals. (2) high voltage power is required, resulting in measurement power consumption. (3) the ultraviolet light source diverges to the periphery, resulting in low utilization. (4) Because of the large volume, a device can only have one fixed wavelength light source. When the difference of ozone concentration ranges is too large, different devices need to be replaced. (5) the service life is shorter. (6) mercury vapor is generated.
In addition, when the wall of the quartz glass is stained or deposited during the ozone measurement, errors may be generated in the light sensing signal measured by the light sensor. However, the existing ozone concentration measuring instrument cannot provide real-time feedback and real-time correction for the error. Therefore, the existing ozone concentration measuring instrument obviously does not meet the requirements of accurate, stable and quick feedback of ozone concentration.
Disclosure of Invention
In order to solve the problems of long preheating time, high starting voltage, low light source utilization rate caused by using a low-pressure mercury lamp as an ultraviolet light source when measuring the concentration of ozone gas in the prior art, and small detection concentration range caused by using a single wavelength in the prior art. One object of the present invention is to provide a gas concentration measuring device for measuring the gas concentration of a gas to be measured.
In order to achieve the above object, the present invention provides a gas concentration measuring apparatus for measuring a gas concentration of a gas to be measured, comprising a gas detection chamber connected to a gas inlet and outlet passage such that a chamber of the gas detection chamber has the gas to be measured, a temperature sensing device for detecting a gas temperature of the gas to be measured, a pressure sensing device for detecting a gas pressure of the gas to be measured, a light source supply device provided at a first side of the gas detection chamber and comprising at least one light emitting source for providing a first detection beam and a correction beam, wherein a light absorption of the gas to be measured to the first detection beam is greater than a light absorption of the gas to be measured to the correction beam, and a light splitting device for splitting the first detection beam into a first detection beam and a second detection beam and splitting the correction beam into a first correction beam and a second correction beam, wherein the first detection beam and the first correction beam have light intensities of the gas to be measured passing through the gas detection chamber and the gas to be measured in the gas detection chamber, respectively, the light source supply device comprises a light intensity measuring device for calculating a light intensity of the first detection beam and the correction beam, respectively, and a light splitting device for measuring a light intensity of the first detection beam and a light beam by the first detection beam and a light splitting device for measuring a light intensity of the first detection beam and a light, and calculating a corrected concentration of the gas to be measured, wherein the first detected concentration is subtracted from the corrected concentration to obtain the gas concentration of the gas to be measured.
Wherein, the two ends of the gas inlet and outlet channel are respectively a channel air inlet and a channel air outlet for correspondingly leading in and leading out the gas to be tested, the gas detection cavity is a hollow cavity with the cavity, the two ends of the hollow cavity are respectively provided with a detection air inlet and a detection air outlet which are communicated with the cavity of the hollow cavity, wherein the gas to be tested continuously flows through the cavity of the hollow cavity of the gas detection cavity.
Wherein the gas concentration measuring device further comprises a processing component for calculating the first detection concentration of the gas to be measured according to the gas temperature of the gas to be measured, the gas pressure of the gas to be measured, the light intensity of the first detection beam, the light intensity of the second detection beam, an optical path length of the gas to be measured in the chamber of the gas detection chamber and an absorption coefficient of the gas to be measured, wherein the processing component further calculates the correction concentration of the gas to be measured according to the gas temperature of the gas to be measured, the gas pressure of the gas to be measured, the light intensity of the first correction beam, the light intensity of the second correction beam, the optical path length of the gas to be measured in the chamber of the gas detection chamber and the absorption coefficient of the gas to be measured.
Wherein the gas to be measured is ozone, and the first detection beam and the correction beam provided by the light source are ultraviolet light.
The light splitting component is an inclined light splitting piece, so that the first detection light splitting component and the first correction light splitting component have the same first light path, and the second detection light splitting component and the second correction light splitting component have the same second light path.
Wherein the gas detection chamber is a quartz glass tube.
Wherein the wavelength of the first detection beam is located within an absorption wavelength range of the gas to be detected, and the wavelength of the correction beam is located outside the absorption wavelength range of the gas to be detected, so as to correct a light absorption interference error generated by the gas detection cavity.
Wherein the light source supply device further comprises a light source control component for controlling the light source of the light source supply device to alternately provide the first detection light beam and the correction light beam in a light emitting mode.
Wherein, the light emitting mode provides the first detection light beam and the correction light beam for pulse or interval opening and closing.
When the gas concentration of the gas to be measured obtained by subtracting the correction concentration from the first detection concentration is lower than a default value, the light source provides at least one second detection light beam to replace the first detection light beam, and the wavelength and/or brightness of the second detection light beam is different from that of the first detection light beam.
The light source is provided with one or a plurality of light emitting components for providing the first detection light beam and the correction light beam.
In order to achieve the above object, the present invention further provides a method for measuring a gas concentration of a gas under test, comprising the steps of providing a gas detection chamber, the gas detection chamber being connected to a gas inlet/outlet channel such that a chamber of the gas detection chamber has the gas under test, performing a temperature detection step for detecting a gas temperature of the gas under test, performing a pressure detection step for detecting a gas pressure of the gas under test, providing a first detection beam and a calibration beam, wherein a brightness of the gas under test with respect to the first detection beam is greater than a brightness of the gas under test with respect to the calibration beam, performing a spectroscopic step for dividing the first detection beam into a first detection spectroscopic and a second detection spectroscopic and dividing the calibration beam into a first calibration spectroscopic and a second calibration spectroscopic respectively, and performing a first calibration spectroscopic and a second calibration spectroscopic respectively, for calculating a first calibration light intensity and a calibration light intensity, respectively, and performing a first calibration light intensity and a calibration light intensity, respectively, for calculating a first calibration light concentration and a calibration light concentration, respectively, and performing a calibration light and a calibration light, respectively, for measuring the first calibration light and the first calibration light intensity.
Wherein the gas to be measured continuously flows through the chamber of the gas detection chamber.
Wherein the light intensity measuring step further comprises calculating the first detection concentration of the gas under test according to the gas temperature of the gas under test, the gas pressure of the gas under test, the light intensity of the first detection beam, the light intensity of the second detection beam, an optical path length of the gas under test in the chamber of the gas detection chamber and an absorption coefficient of the gas under test, and the correcting step further comprises calculating the correction concentration of the gas under test according to the gas temperature of the gas under test, the gas pressure of the gas under test, the light intensity of the first correction beam, the light intensity of the second correction beam, the optical path length of the gas under test in the chamber of the gas detection chamber and the absorption coefficient of the gas under test.
The gas to be detected is ozone, and the first detection light beam and the correction light beam are ultraviolet light.
The light splitting step is to make the first detection light splitting and the first correction light splitting have the same first light path by a light splitting component, and the second detection light splitting and the second correction light splitting have the same second light path.
Wherein the gas detection chamber is a quartz glass tube.
Wherein the wavelength of the first detection beam is located within an absorption wavelength range of the gas to be detected, and the wavelength of the correction beam is located outside the absorption wavelength range of the gas to be detected, so as to correct a light absorption interference error generated by the material of the gas detection cavity.
The method further comprises controlling a light source to alternately provide the first detection beam and the correction beam in a light emitting mode by a light source control component.
Wherein, the light emitting mode provides the first detection light beam and the correction light beam for pulse or interval opening and closing.
When the gas concentration of the gas to be measured obtained by subtracting the correction concentration from the first detection concentration is lower than a default value, at least one second detection light beam is provided to replace the first detection light beam, and the wavelength and/or brightness of the second detection light beam is different from that of the first detection light beam.
The method further comprises providing the first detection beam and the correction beam by one or more light emitting elements.
As described above, the gas concentration measuring apparatus and method of the present invention have the following effects:
(1) Compared with the traditional technology adopting a low-pressure mercury lamp as an ultraviolet light source, the gas concentration measuring device adopts the light-emitting diode component with small volume as an ultraviolet light source (UV-LED) and can respond to ozone gas with different concentration ranges, so that a machine is not required to be replaced.
(2) The invention uses the LED component as the ultraviolet light source without starting up preheating time, so the ultraviolet light source can be provided in a pulse switch mode, and the effect of real-time correction is achieved.
(3) The invention uses the LED component as the ultraviolet light source to accurately and rapidly measure the gas concentration of the continuously flowing gas to be measured in real time, and has the advantages of no need of preheating, low starting voltage, no mercury vapor and long service life.
(4) The invention can change the detection light beams with different wavelengths in real time according to the gases to be detected with different concentration ranges, thereby providing real-time correction and feedback.
(5) The invention can solve the problem of measurement error caused by dirty quartz glass tube wall in the traditional technology.
In order to further understand and appreciate the technical features and effects of the present invention, a preferred embodiment and a detailed description are provided.
Drawings
FIG. 1 is a flow chart of a method for measuring gas concentration according to the present invention.
FIG. 2 is a schematic diagram of a gas concentration measuring apparatus according to the present invention, in which a light-emitting source generates a first detection beam.
FIG. 3 is a schematic diagram of a gas concentration measuring apparatus according to the present invention, in which a light emitting source generates a correction beam.
FIG. 4 is a schematic diagram of a gas concentration measuring apparatus according to the present invention, in which a light-emitting source generates a second detection beam.
FIG. 5 is a schematic diagram showing the operation of a light source supply device of the gas concentration measuring device of the present invention.
Reference numerals illustrate:
10 gas inlet and outlet channels
12, Air inlet of channel
14, Air outlet hole of channel
20 Gas detection chamber
22 Chamber
24 Hollow cavity
26 Detecting the air inlet
28, Detecting the air outlet hole
30 Temperature sensing Assembly
40 Pressure sensing assembly
42 Pressure sensing air inlet port
50 Light source supply device
51 Cover body
52 Luminous source
52A first LED assembly
52B second LED assembly
52C third LED assembly
54:
55 first detection beam
55A first detection beam split
55B second detection spectroscopic
56 Correction of the beam
56A first corrected spectroscopic
56B second correction beam splitting
57 Second detection beam
60 Photo-sensing device
62 First photo-sensing component
64 Second light sensing component
70 Processing assembly
80 Light source control assembly
100 Gas concentration measuring device
200 Gas to be measured
S10, S12, S14, S16, S18, S20, S22 step
T1, t2 interval
Detailed Description
For the purpose of promoting an understanding of the principles of the invention, including its principles, its advantages, and its advantages, reference should be made to the drawings and to the accompanying drawings, in which there is illustrated and described herein a specific example of an embodiment of the invention. In addition, for ease of understanding, like elements in the following embodiments are denoted by like reference numerals.
Furthermore, the terms used throughout the specification and claims, unless otherwise indicated, shall generally be construed to have the ordinary meaning and meaning given to each term in the art, both in the context of the disclosure and in the specific context. Certain words used to describe the invention will be discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing the invention.
The use of "first," "second," "third," and the like herein does not specifically refer to order or sequence, nor is it intended to limit the invention to only distinguish between components or operations that may be described in the same technical term.
Second, the words "comprising," "including," "having," "containing," and the like, as used herein, are open-ended terms, meaning including, but not limited to.
In order to solve the problems of long preheating time, high starting voltage and low light source utilization rate caused by using a low-pressure mercury lamp as an ultraviolet light source when measuring the concentration of ozone gas in the prior art, and small detection concentration range caused by using a single wavelength in the prior art. The present invention provides a gas concentration measuring device and method for measuring the gas concentration of a gas to be measured (e.g. ozone flowing continuously). The light source of the light source supply device of the present invention provides at least one (including) ultraviolet wavelength to accurately and rapidly measure the ozone concentration. The invention can solve the problem that the low-pressure mercury lamp is used as an ultraviolet light source in the traditional technology and the problem of measurement error caused by dirty quartz glass tube wall in the traditional technology.
Referring to fig. 1 to 5, fig. 1 is a flow chart of a gas concentration measuring method according to the present invention, and fig. 2 is a schematic diagram of a gas concentration measuring device according to the present invention, wherein a light emitting source generates a first detection beam. FIG. 3 is a schematic diagram of a gas concentration measuring apparatus according to the present invention, in which a light emitting source generates a correction beam. FIG. 4 is a schematic diagram of a gas concentration measuring apparatus according to the present invention, in which a light-emitting source generates a second detection beam. FIG. 5 is a schematic diagram showing the operation of a light source supply device of the gas concentration measuring device of the present invention.
As shown in FIG. 1, and referring to FIGS. 2 to 5, the gas concentration measuring method of the present invention at least comprises the steps of providing a gas detection chamber, wherein the gas detection chamber is connected to a gas inlet/outlet passage, such that a chamber of the gas detection chamber is provided with a gas to be measured, performing a temperature detection step for detecting a gas temperature of the gas to be measured, performing a pressure detection step for detecting a gas pressure of the gas to be measured, providing a first detection beam and a correction beam, wherein an absorption brightness of the gas to be measured for the first detection beam is greater than an absorption brightness of the gas to be measured for the correction beam, performing a beam splitting step for splitting the first detection beam into a first detection beam and a second detection beam having a passing and a non-passing gas detection chamber and the gas to be measured therein, and splitting the correction beam into a first correction beam and a second correction beam having a passing and a non-passing gas detection chamber and the gas to be measured therein, respectively. A step S20 of measuring the light intensity of the first detection beam after passing through the gas to be measured and the light intensity of the second detection beam, respectively, wherein the light intensity variation in the light intensity measuring step is caused by the gas to be measured and the gas detection chamber, thereby calculating the first detection concentration of the gas to be measured, and a step S22 of correcting the light intensity of the first correction beam after passing through the gas to be measured and the light intensity of the second correction beam, respectively, wherein the light intensity variation in the correcting step is caused by the gas detection chamber, thereby calculating the correction concentration of the gas to be measured (i.e. the error caused by the gas detection chamber), wherein the first detection concentration is subtracted from the correction concentration, thereby obtaining the gas concentration of the gas to be measured. Although the gas concentration measuring method is illustrated in the above-mentioned sequence of steps, the present invention is not limited thereto, and any sequence of steps, even adding or subtracting steps, is contemplated as long as the gas concentration of the gas to be measured can be obtained.
The gas concentration measuring device 100 of the present invention at least comprises a gas detecting chamber 20, a temperature sensing component 30, a pressure sensing component 40, a light source supplying device 50 and a light sensing device 60. The gas detection chamber 20 is connected to the gas inlet/outlet channel 10, so that the chamber 22 of the gas detection chamber 20 has a gas 200 to be measured, thereby measuring the gas concentration of the gas 200 to be measured. The two ends of the gas inlet/outlet channel 10 are respectively provided with a channel inlet hole 12 and a channel outlet hole 14 for correspondingly guiding in and guiding out the gas 200 to be measured. Although the present invention is exemplified by the gas concentration measuring apparatus and method using ozone as the gas 200 to be measured, the present invention is not limited thereto, and any gas is suitable for the gas concentration measuring apparatus and method of the present invention and falls within the scope of the present invention.
The gas inlet 12 of the gas inlet/outlet channel 10 is connected to a gas supply source (not shown), for example, so as to introduce the gas 200 provided by the gas supply source into the gas inlet/outlet channel 10. The gas inlet/outlet 14 of the gas inlet/outlet 10 is, for example, connected to a gas application end (not shown), such as, but not limited to, a sterilization apparatus or a semiconductor wafer processing chamber. The gas under test 200, the gas under test supply source, and the gas under test application of the present invention are not limited to the examples described above, and any gas under test supply source and all possible applications are within the scope of the present invention.
The gas detecting chamber 20 is connected to the gas inlet/outlet passage 10, for example, between two ends of the gas inlet/outlet passage 10, wherein the gas detecting chamber 20 is a quartz glass tube made of transparent material such as quartz glass, and at least the upper and lower ends of the quartz glass tube are made of transparent material such as quartz glass. The gas detection chamber 20 is not limited to quartz glass, and may be made of other materials, so long as it has low or no absorption brightness for the detection beam and the correction beam. The gas detecting chamber 20 is, for example, a hollow chamber 24 having a chamber 22, and the two ends of the hollow chamber 24 are respectively provided with a detecting inlet hole 26 and a detecting outlet hole 28 communicated with the chamber 22 of the hollow chamber 24. The gas 200 to be measured is, for example, a chamber 22 that continuously flows through a hollow cavity 24 of the gas detection chamber 20.
The temperature sensor 30 is disposed on the gas inlet/outlet channel 10, for example, and is used for detecting the gas temperature of the gas 200 to be measured. The pressure sensing component 40 is disposed in the gas inlet/outlet channel 10, and is connected to the interior of the gas inlet/outlet channel 10 via the pressure sensing inlet port 42, for detecting the gas pressure of the gas 200 to be measured in the interior of the gas inlet/outlet channel 10. However, the types, types and installation positions of the temperature sensing element 30 and the pressure sensing element 40 are not particularly limited. In the embodiment of the present invention, the temperature sensing element 30 and the pressure sensing element 40 may be any existing commercially available elements and may be disposed on the gas inlet/outlet channel 10, the gas detection chamber 20 and/or the gas supply source to be tested, so long as the temperature and pressure of the gas to be tested 200 can be detected.
The light source supply device 50 of the gas concentration measuring device 100 of the present invention comprises at least a light emitting source 52 and a Beam Splitter (Beam Splitter) 54. The present invention can divide the beam emitted from the light source 52 of the light source supply device 50 into two sub-beams by the beam dividing component 54, wherein the two sub-beams are respectively passing through and not passing through the gas to be measured 200 in the gas detection chamber 20. The intensities of the two sub-beams are then measured separately using the photo-sensor device 60. If the gas 200 to be measured has a higher absorption intensity for the above-mentioned light beams, the difference in the intensities of the two sub-beams will come from the gas 200 to be measured and the gas detection chamber 20, i.e. the attenuation of the light intensity is caused by the gas 200 to be measured and the gas detection chamber 20. However, when the measured gas 200 has a lower absorption intensity (the lower the absorption intensity is, the better the absorption intensity is, or even no absorption intensity is, the better the absorption intensity is), the difference between the intensities of the two sub-beams will only come from the gas detection chamber 20, i.e. the attenuation of the light intensity is caused by the gas detection chamber 20 only, such as the light absorption interference error caused by the wall dirt or sediment of the gas detection chamber 20. In other words, the present invention can provide two light beams with different wavelengths (i.e. high and low or no absorption intensities of the gas to be measured) by the light source 52, and can accurately detect the gas concentration of the gas to be measured 200 by subtracting the light absorption interference error caused by the wall dirt or sediment of the gas detection chamber 20.
In the embodiment of the present invention, the light source supplying device 50 is disposed on a first side of the gas detecting chamber 20, for example, to provide a first detecting light beam 55 and a correcting light beam 56 on the first side of the gas detecting chamber 20 by using the light emitting source 52. The light source 52 is, for example, a light emitting diode (led) assembly, so as to improve the conventional uv light source from being diffused all around, resulting in low utilization. The light source supplying device 50, for example, but not limited to, has a cover 51 disposed on the first side of the gas detecting chamber 20, and the light source 52 and the light splitting component 54 are disposed inside the cover 51, however, the cover 51 is not limited to having a hollow interior or a solid interior. For example, the present invention may generate the first detection beam 55 by the first Light Emitting Diode (LED) 52a and the correction beam 56 by the second LED 52b, respectively. However, the present invention is not limited thereto, and the present invention may also generate the first detection beam 55 and the correction beam 56 by a single Light Emitting Diode (LED), for example. One feature of the present invention is that the luminance of the first detecting beam 55 is preferably greater than the luminance of the correcting beam 56 by the detecting gas 200, wherein the difference between the two luminance values is greater. For example, the wavelength of the first detection beam 55 is within the absorption wavelength range of the gas to be measured 200, and the wavelength of the correction beam 56 may be within or outside the absorption wavelength range of the gas to be measured 200, so long as the absorption brightness of the gas to be measured 200 to the first detection beam 55 is greater than the absorption brightness of the gas to be measured 200 to the correction beam 56, which is applicable to the present invention. Wherein the wavelength of the correction beam 56 is preferably outside the absorption wavelength range of the gas under test 200, i.e., when the correction beam 56 passes through the gas under test 200 in the chamber 22 of the gas detection chamber 20, the correction beam 56 is not absorbed by the gas under test 200, so that the error caused by the gas detection chamber 20 can be obtained. Taking the gas to be measured as ozone for example, the first detecting beam 55 and the correcting beam 56 are ultraviolet light with different wavelengths, the wavelength range is between about 200nm and about 370nm, or the correcting beam 56 is outside the wavelength range, wherein the ultraviolet light absorption brightness of the first detecting beam 55 is higher than the ultraviolet light absorption brightness of the correcting beam 56. The absorption spectrum of ozone is between about 200nm and about 370nm, and the maximum absorption wavelength is about 254nm. Therefore, the present invention can, for example, select a first LED element 52a having an ultraviolet wavelength of 254nm with a maximum absorption of ozone gas to generate the first detection beam 55, and select a second LED element 52b having an ultraviolet wavelength of 385nm with a minimum absorption of ozone gas to generate the correction beam 56. In addition, the present invention is preferably an alternating (e.g., a staggered manner such as a staggered manner) turns on and off the first led assembly 52a and the second led assembly 52b. For example, the pulse width may be, for example, any value between 0.1ms and 5ms, the period may be, for example, any value between 0.1s and 1s, and the frequency may be, for example, any value between 100Hz and 1 Hz. Taking the example of interval, the present invention can repeat the turning on and off of the first detection beam 55 and the correction beam 56, for example, at regular time intervals. The above data are only examples and are not intended to limit the scope of the present invention. As shown in fig. 2 and 5, the interval (t 1) represents that the first led element 52a is in an on state, and the second led element 52b is in an off state. As shown in fig. 3 and 5, the interval (t 2) represents that the first led element 52a is in the off state, and the second led element 52b is in the on state. The above-mentioned interval is, for example, a time interval. According to the beer-lambert law, the invention can detect ozone gas in the Hartley-Huggins spectrum absorption band (200 nm-370 nm). For example, the maximum concentration of ozone gas that can be detected in the present invention can be, for example, about 400g/Nm 3, where g is grams and Nm 3 is standard cubic meters. Alternatively, for example, the concentration of ozone gas detectable by the present invention may range from 1ppm to 250 ppm.
As before, the beam splitter 54 of the present invention can split the first detection beam 55 into a first detection beam 55a and a second detection beam 55b (as shown in FIG. 2), and split the correction beam 56 into a first correction beam 56a and a second correction beam 56b (as shown in FIG. 3), wherein the first detection beam 55a and the first correction beam 56a have the gas 200 passing through the gas detection chamber 20 and the gas 200 therein, and the second detection beam 55b and the second correction beam 56b have no gas 200 passing through the gas detection chamber 20 and the gas 200 therein. The beam splitter 54 is, for example, an inclined beam splitter, and is disposed between the light source 52 and a second light sensor 64 (described below), so that the first detection beam 55a and the first correction beam 56a have the same first optical path, and the second detection beam 55b and the second correction beam 56b have the same second optical path.
In addition, the light sensing device 60 of the gas concentration measuring device 100 of the present invention at least comprises a first light sensing component 62 and a second light sensing component 64 respectively located at the second side and the first side of the gas detection chamber 20. The first detection beam 55 (ultraviolet light) provided by the light source 52 of the present invention passes through the beam splitter 54 and then reaches the first light sensor 62 along the first optical path through the gas detection chamber 20 made of quartz glass to establish the light intensity of the gas 200 (ozone gas) and the gas detection chamber 20, and the second detection beam 55b provided by the light source 52 passes through the beam splitter 54 and then reaches the second light sensor 64 along the second optical path to establish the light intensity of the gas 200 (ozone gas) and the gas detection chamber 20. Similarly, the present invention can also respectively establish the light intensities of the gas 200 (ozone gas) to be measured and the gas detection chamber 20 and the light intensities of the gas 200 (ozone gas) not to be measured and the gas detection chamber 20 not to be measured for the first correction beam 56a and the second correction beam 56b of the correction beam 56 provided by the light-emitting source 52.
According to the beer-lambert law, which is well known to those skilled in the art, when light passes through a gas, the absorbance (or brightness, absorbance) of the light is proportional to the absorption coefficient (absorption coefficient), the optical path length and the gas concentration. Therefore, the present invention can calculate the first detection concentration and the correction concentration of the gas 200 to be measured, for example, by using the beer-lambert law, and deduct the correction concentration from the first detection concentration to obtain the gas concentration of the gas 200 to be measured.
Briefly, the first optical sensing element 62 and the second optical sensing element 64 of the optical sensing device 60 of the present invention can measure the light intensity of the first detection beam 55a and the light intensity of the second detection beam 55b, respectively, so as to calculate the first detection concentration of the gas 200 to be measured, and measure the light intensity of the first correction beam 56a and the light intensity of the second correction beam 56b of the correction beam 56, respectively, so as to calculate the correction concentration of the gas 200 to be measured, wherein the gas concentration of the gas 200 to be measured can be obtained after the first detection concentration is subtracted from the correction concentration.
Calculating the concentration of each gas according to the beer-lambert lawThe formula: Taking the gas 200 to be measured as ozone as an example, I is a value of UV light intensity (first optical path) containing ozone gas, I 0 is a value of UV light intensity (second optical path) not containing ozone gas, α is an absorption coefficient of ozone gas, P is a gas pressure of ozone gas, T is a gas temperature (in degrees K) of ozone gas, psi is a pressure (in pounds per square inch (absolute)), and l is an optical path length of ozone gas.
In detail, the gas concentration measuring device 100 of the present invention may further include a processing device 70, wherein the processing device 70 is electrically connected to the light sensing device 60, the temperature sensing device 30 and the pressure sensing device 40, and the processing device 70 is a processing control device. The processing unit 70, for example, takes the gas temperature of the gas to be measured 200, the gas pressure of the gas to be measured 200, the light intensity of the first detection beam 55a, the light intensity of the second detection beam 55b, the optical path length of the gas to be measured 200 in the chamber 22 of the gas detection chamber 20 and the absorption coefficient of the gas to be measured 200 into the ratio of the concentration of each gas as disclosed in the beer-lambert lawIn the formula, a first detection concentration of the gas 200 to be measured is calculatedWherein the processing component 70 further calculates the ozone concentration by, for example, bringing the gas temperature of the gas under test 200, the gas pressure of the gas under test 200, the light intensity of the first correction light beam 56a, the light intensity of the second correction light beam 56b, the optical path length of the gas under test 200 in the chamber 22 of the gas detection chamber 20 and the absorption coefficient of the gas under test 200 into the beer-lambert lawThe formula calculates the corrected concentration of the gas 200 to be measuredWherein the first detection concentrationDeducting the corrected concentrationThe gas concentration of the gas 200 to be measured can be obtained(I.e.,)。
The light source supply device 50 of the present invention further optionally includes a light source control component 80 for controlling the light source 52 of the light source supply device 50 to alternately provide the first detection beam 55 and the correction beam 56 in a light emitting mode. For example, the light source control assembly 80 is such as, but not limited to, an ultraviolet light source pulse controller. The processing assembly 70 may be electrically connected to the light source control assembly 80, for example. Wherein, the light emitting mode is, for example, pulsed or intermittent on and off to provide the first detection beam 55 and the correction beam 56. In addition, the light source 52 has one or more light emitting components for providing a first detection beam 55 and a correction beam 56. For example, the present invention may provide the first detection beam 55 and the correction beam 56 by a plurality of light emitting elements, such as the first light emitting diode element 52a and the second light emitting diode element 52b, respectively. The first LED assembly 52a, for example, generates a first detection beam 55, and the second LED assembly 52b, for example, generates a correction beam 56. However, the present invention is not limited thereto, and since a single Light Emitting Diode (LED) may also include a plurality of solid-state LED dies with different wavelengths, the present invention may also generate the first detection beam 55 and the correction beam 56 by a single light emitting component (e.g., LED) respectively. In addition, the brightness and/or wavelength of the first detection beam 55 and the correction beam 56 can be adjusted by the light source control device 80.
Furthermore, the present invention is characterized in that when the first detected concentration is measuredDeducting the corrected concentrationThe gas concentration of the gas to be measured 200 obtainedBelow a predetermined value, the light source 52 may provide at least one second detection beam 57 instead of the first detection beam 55, as shown in fig. 4. The beam splitter 54 also splits the second detection beam 57 into a third detection beam 57a and a fourth detection beam 57b to obtain a first detection concentration as the first detection beam 55Wherein the wavelength and/or brightness of the second detection beam 57 is different from the wavelength and/or brightness of the first detection beam 55. Wherein the first detection concentrationDeducting the corrected concentrationThe gas concentration of the gas 200 to be measured can be obtained(I.e.,). The invention is not limited to changing the wavelength or brightness of the detection beam in manual or automatic mode. Taking the automatic mode to change the wavelength of the detection beam as an example, when the gas concentration of the gas 200 (e.g., ozone) to be detected is detected to be lower than a certain default value, for example, lower than 10% of the default scale (e.g., full scale), the light source control component 80 may, for example, control the light emitting source 52 to provide the second detection beam 57 in real time or subsequently change to the third light emitting diode component 52c, wherein the third light emitting diode component 52c is, for example, a low concentration ozone absorption light source. However, the present invention is not limited thereto, and the present invention may also be used to generate the second detection beam 57 instead of the first detection beam 55 by a single Light Emitting Diode (LED), for example. The light emission pattern between the second detection beam 57 and the correction beam 56 is, for example, the same as the light emission pattern between the first detection beam 55 and the correction beam 56.
The invention can accurately detect the gas concentration of the gas to be detected in real time by utilizing the characteristic that the same gas to be detected (such as ozone) has different absorption degrees for the light rays with different wavelengths and the characteristic that the absorption degree of the light rays with the same wavelength corresponds to the gas concentration of the gas to be detected (such as ozone). Although the present invention is illustrated by taking the gas to be measured as ozone, the present invention is not limited thereto, and any gas can be used to measure the gas concentration of the gas by using the gas concentration measuring device and method of the present invention as long as the gas has different absorption brightness for different light wavelengths. The invention can be used for measuring and correcting the gas to be measured in a flowing or non-flowing state, even can be used for measuring and correcting the continuously flowing gas to be measured in real time, for example, can be used for feeding back a gas supply source to be measured (such as an ozone generator or sterilization equipment) so as to generate ozone gas with sufficient concentration. For example, if the gas to be measured is supplied from the gas supply source in a continuous flow manner, the present invention can also achieve the effect of measuring the gas concentration of the gas to be measured in a continuous flow manner accurately and rapidly in real time, and can also provide the effect of real-time calibration by replacing the detection beam with a corresponding wavelength in real time, for example, in response to the gas to be measured in different concentration ranges. The gas concentration measuring device and method of the present invention can be applied to a gas application end to be measured of a device which needs to accurately, stably and rapidly feed back ozone concentration, such as a sterilizing device, a semiconductor wafer manufacturing device or an ozone generator.
In summary, the gas concentration measuring device and method of the present invention have the following effects:
(1) Compared with the traditional technology adopting a low-pressure mercury lamp as an ultraviolet light source, the gas concentration measuring device adopts the light-emitting diode component with small volume as the ultraviolet light source, and can respond to ozone gas with different concentration ranges, so that a machine is not required to be replaced.
(2) The invention uses the LED component as the ultraviolet light source without starting up preheating time, so the ultraviolet light source can be provided in a pulse switch mode, and the effect of real-time correction is achieved.
(3) The invention uses the LED component as the ultraviolet light source to accurately and rapidly measure the gas concentration of the continuously flowing gas to be measured in real time, and has the advantages of no need of preheating, low starting voltage, no mercury vapor and long service life.
(4) The invention can change the detection light beams with different wavelengths in real time according to the gases to be detected with different concentration ranges, thereby providing real-time correction and feedback.
(5) The invention can solve the problem of measurement error caused by dirty quartz glass tube wall in the traditional technology.
The foregoing is by way of example only and is not intended as limiting. Any equivalent modifications or variations to the present invention without departing from the spirit and scope thereof are intended to be included in the following claims.
Claims (22)
1. A gas concentration measuring apparatus for measuring a gas concentration of a gas to be measured, comprising:
a gas detection cavity which is communicated with a gas inlet and outlet passage, so that one cavity of the gas detection cavity is provided with the gas to be detected;
a temperature sensing component for detecting a gas temperature of the gas to be measured;
a pressure sensing component for detecting a gas pressure of the gas to be measured;
A light source supply device disposed on a first side of the gas detection chamber, comprising:
at least one light source for providing a first detection beam and a correction beam, wherein the absorption of the first detection beam by the gas to be measured is greater than the absorption of the correction beam by the gas to be measured, and
A beam splitter for splitting the first detection beam into a first detection beam and a second detection beam, and splitting the correction beam into a first correction beam and a second correction beam, wherein the first detection beam and the first correction beam pass through the gas detection chamber and the gas to be detected in the gas detection chamber, the second detection beam and the second correction beam do not pass through the gas detection chamber and the gas to be detected in the gas detection chamber, and
The light sensing device at least comprises a first light sensing component and a second light sensing component which are respectively positioned at a second side and the first side of the gas detection cavity and are used for respectively measuring the light intensity of the first detection light beam and the light intensity of the second detection light beam of the first detection light beam so as to calculate a first detection concentration of the gas to be detected, and respectively measuring the light intensity of the first correction light beam and the light intensity of the second correction light beam of the correction light beam so as to calculate a correction concentration of the gas to be detected, wherein the first detection concentration is subtracted from the correction concentration to obtain the gas concentration of the gas to be detected.
2. The apparatus of claim 1, wherein the gas inlet and outlet channels are provided with a channel inlet and a channel outlet, respectively, for introducing and discharging the gas to be measured, the gas detection chamber is a hollow chamber having the chamber, and the two ends of the hollow chamber are provided with a detection inlet and a detection outlet, respectively, which are connected to the chamber of the hollow chamber, wherein the gas to be measured continuously flows through the chamber of the hollow chamber of the gas detection chamber.
3. The gas concentration measuring apparatus of claim 1, further comprising a processing component for calculating the first detected concentration of the gas under test based on the gas temperature of the gas under test, the gas pressure of the gas under test, the light intensity of the first detection beam, the light intensity of the second detection beam, an optical path length of the gas under test in the chamber of the gas detection chamber, and an absorption coefficient of the gas under test, wherein the processing component further calculates the corrected concentration of the gas under test based on the gas temperature of the gas under test, the gas pressure of the gas under test, the light intensity of the first correction beam, the light intensity of the second correction beam, the optical path length of the gas under test in the chamber of the gas detection chamber, and the absorption coefficient of the gas under test.
4. The apparatus of claim 1, wherein the gas to be measured is ozone and the first detecting beam and the correcting beam provided by the light source are ultraviolet light.
5. The apparatus of claim 1, wherein the beam splitter is a tilted beam splitter, such that the first detection beam splitter and the first calibration beam splitter have a same first optical path, and the second detection beam splitter and the second calibration beam splitter have a same second optical path.
6. The gas concentration measuring device of claim 1, wherein the gas detection chamber is a quartz glass tube.
7. The gas concentration measuring apparatus of claim 1, wherein the wavelength of the first detection beam is within an absorption wavelength range of the gas under test, and the wavelength of the correction beam is outside the absorption wavelength range of the gas under test, thereby correcting a light absorption interference error generated by the gas detection chamber.
8. The gas concentration measuring device according to claim 1, wherein the light source supplying device further comprises a light source control unit for controlling the light source of the light source supplying device to alternately supply the first detection beam and the correction beam in a light-emitting mode.
9. The apparatus of claim 8, wherein the illumination mode is pulsed or intermittent on and off to provide the first detection beam and the calibration beam.
10. The apparatus according to claim 1 or 8, wherein the light source provides at least one second detection beam instead of the first detection beam when the gas concentration of the gas to be measured obtained by subtracting the correction concentration from the first detection concentration is lower than a predetermined value, the wavelength and/or brightness of the second detection beam being different from the wavelength and/or brightness of the first detection beam.
11. The gas concentration measuring device of claim 10, wherein the light source has one or more light emitting elements for providing the first detection beam and the correction beam.
12. A gas concentration measuring method is characterized in that the method is used for measuring a gas concentration of a gas to be measured and comprises the following steps:
providing a gas detection cavity which is communicated with a gas inlet and outlet passage, so that one cavity of the gas detection cavity is provided with the gas to be detected;
performing a temperature detection step for detecting a gas temperature of the gas to be detected;
Performing a pressure detection step for detecting a gas pressure of the gas to be detected;
Providing a first detection beam and a correction beam, wherein the absorption brightness of the gas to be detected for the first detection beam is greater than the absorption brightness of the gas to be detected for the correction beam;
Performing a beam splitting step for splitting the first detection beam into a first detection beam and a second detection beam respectively having and not having passed through the gas to be detected in the gas detection chamber and splitting the correction beam into a first correction beam and a second correction beam respectively having and not having passed through the gas to be detected in the gas detection chamber and the gas detection chamber;
performing a light intensity measuring step for measuring a light intensity of the first detection beam and a light intensity of the second detection beam, respectively, to calculate a first detection concentration of the gas to be detected, and
Performing a calibration step for measuring a light intensity of the first calibration beam and a light intensity of the second calibration beam, respectively, to calculate a calibration concentration of the gas to be measured, wherein the first calibration concentration is subtracted from the first calibration concentration to obtain the gas concentration of the gas to be measured.
13. The method of claim 12, wherein the test gas flows continuously through the chamber of the gas detection chamber.
14. The method according to claim 12, wherein the light intensity measuring step further comprises calculating the first detection concentration of the gas under test based on the gas temperature of the gas under test, the gas pressure of the gas under test, the light intensity of the first detection beam, the light intensity of the second detection beam, an optical path length of the gas under test in the chamber of the gas detection chamber and an absorption coefficient of the gas under test, and the correcting step further comprises calculating the correction concentration of the gas under test based on the gas temperature of the gas under test, the gas pressure of the gas under test, the light intensity of the first correction beam, the light intensity of the second correction beam, the optical path length of the gas under test in the chamber of the gas detection chamber and the absorption coefficient of the gas under test.
15. The method of claim 12, wherein the gas to be measured is ozone, and the first detecting beam and the correcting beam are ultraviolet light.
16. The method of claim 12, wherein the splitting step includes a splitting component to make the first detection beam and the first correction beam have a same first optical path, and the second detection beam and the second correction beam have a same second optical path.
17. The method of claim 12, wherein the gas detection chamber is a quartz glass tube.
18. The method of claim 12, wherein the first detection beam has a wavelength within an absorption wavelength range of the gas to be measured, and the correction beam has a wavelength outside the absorption wavelength range of the gas to be measured, so as to correct a light absorption interference error generated by a material of the gas detection chamber.
19. The method of claim 12, further comprising controlling a light source to alternately provide the first detection beam and the correction beam in a light pattern by a light source control unit.
20. The method of claim 19, wherein the light emitting pattern is pulsed or intermittent on and off to provide the first detection beam and the calibration beam.
21. The method according to claim 12 or 18, wherein when the gas concentration of the gas to be measured obtained by subtracting the corrected concentration from the first detected concentration is lower than a predetermined value, at least one second detecting beam is provided instead of the first detecting beam, and the wavelength and/or brightness of the second detecting beam is different from the wavelength and/or brightness of the first detecting beam.
22. The method of claim 21, further comprising providing the first detection beam and the calibration beam using a light source having one or more light emitting elements.
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| CN202311206186.1A CN119666770A (en) | 2023-09-19 | 2023-09-19 | Gas concentration measuring device and method |
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| CN202311206186.1A CN119666770A (en) | 2023-09-19 | 2023-09-19 | Gas concentration measuring device and method |
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